This invention relates to a device for starting an engine and generating power which is connected to an internal combustion engine, for starting the engine as a starting motor and serving as a generator after the starting.
In a general conventional device for starting an engine and generating power attached with a planetary gear, as shown for instance, in Japanese Unexamined Patent Publication No. 81563/1991, no special cooling device is provided for an armature coil and a field coil. FIG. 4 is a sectional diagram showing a conventional device for starting engine and generating power. As shown in FIG. 4, the device is constructed by a rotating body 103 integrated with a first rotor 101a and a second rotor 101b by a ring 102, a field coil 105 wound with a field core 104, and an armature coil 106 as major components. This device is not provided with an equipment for cooling the armature coil and the field coil.
There are devices of this kind each of which cools an armature coil and a field coil, disclosed for instance, in Japanese Patent Publication No. 198556/1988 and Japanese Unexamined Patent Publication No. 202257/1988. In both devices for starting up an engine and charging electricity, rotating field poles are attached to a crankshaft of an engine and the field poles are excited by excitation coils. Stator cores provided with stator coils are attached to main bodies of the engines.
In starting, power is supplied to the excitation coil and an AC voltage having a low frequency is supplied to the stator coil thereby synchronizingly rotating the rotating field poles and the device transmits the rotation to the engine as a starting motor. By increasing the frequency of the supplied AC voltage, the rotation of the rotating field poles is increased thereby starting the engine. When the engine is started, the supply of the AC voltage to the stator coil is stopped. Since the rotating field poles are rotated by a crankshaft, an AC voltage is generated in the stator coil, and the device charges electricity through a rectifier as a generator.
In the former device for starting an engine and charging electricity, a cooling solution of the engine per se flows in a cooling water passage surroundingly provided at a back portion of an assembly of the stator core and the stator coil thereby cooling the device.
Furthermore, in the latter device for starting an engine and charging electricity, a thermally conductive ring is provided between a cylinder block or a bracket and a transmission case through a thermally conductive seal cover. A thermally conductive gel is sealed among the cylinder block or the bracket, an inter peripheral portion of the ring and an outer peripheral portion of the stator coil. The heat of the stator coil is transferred to the cylinder block or the bracket and the ring through the thermally conductive gel thereby cooling the device.
In such a conventional device for starting an engine and charging electricity, the rotating field poles are directly connected to the crankshaft. In starting, a large torque output is required at a low speed rotation. Therefore, the device is magnified. Since the revolution speed is below a pertinent value in power generating, the output can not be enhanced. Furthermore, a sealing means is required for the passage of the cooling solution or the thermally conductive gel. Therefore, the structure thereof is complicated, the fabrication thereof is difficult, the price thereof is elevated, and a large amount of time is required for check and maintenance thereof.